Role of the plasmodesmata localized ACR4 and CLV1 receptor kinases in controlling stem cell fate in the root

• Applicant: Professor Dr. Rüdiger Simon
• Subject Area: Plant Cell and Developmental Biology ; Developmental Biology
• Term: from 2014 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 269106198

The homeostasis of the root stem cell domain is achieved by signaling between the quiescent centre (QC), stem cells and the surrounding cells that enter differentiation. It is not yet understood how cells communicate with each other in order to fine tune the balance between proliferation and differentiation. Recent work showed that the membrane associated receptor kinases ACR4 and CLV1, which control stem cell number in the distal root meristem, interact at the sites of plasmodesmata, suggesting that ACR4-CLV1 complexes may regulate the movement of signaling molecules necessary for root meristem homeostasis. In this project we plan to analyze if, and how, ACR4-CLV1 complexes control connectivity between meristem cells, and how this regulation contributes to the maintenance of root homeostasis. Furthermore, we will elucidate the downstream targets of ACR4-CLV1 complexes after perception of the CLE40 peptide. Therefore, we will perform transcript profiling of the QC in comparison with sorted columella stem cells, with or without CLE40 peptide treatment. Additionally, we will employ a genetic screen to identify new components regulating the balance between proliferation and differentiation. Ensuing gene cloning and functional analysis will expand our understanding of the ACR4-CLV1 signalling pathway. The results obtained in the proposed project will help the field in understanding how spatiotemporal communication integrates stem cell behaviour in the root meristem. Thus, this research project will address a fundamental problem in biology: how short range patterns of cells with different identities are generated and maintained, and how cell proliferation and differentiation is controlled by local signaling and is integrated with the growth requirements of the entire organism. Furthermore, understanding the longevity of plant stem niches will allow researchers to improve in general plant growth and biomass production.

• DFG Programme: Research Grants